首先,我找到了这个链接:Objective C HTML转义/反转义,但它对我没有用。
我的编码字符(顺便说一下,来自于一个RSS源)看起来像这样:
我的编码字符(顺便说一下,来自于一个RSS源)看起来像这样:
&
我在网上搜索了相关讨论,但没有针对我的特定编码的解决方法,我认为它们被称为十六进制字符。&
我在网上搜索了相关讨论,但没有针对我的特定编码的解决方法,我认为它们被称为十六进制字符。请查看我的处理HTML的NSString分类。以下是可用的方法:
- (NSString *)stringByConvertingHTMLToPlainText;
- (NSString *)stringByDecodingHTMLEntities;
- (NSString *)stringByEncodingHTMLEntities;
- (NSString *)stringWithNewLinesAsBRs;
- (NSString *)stringByRemovingNewLinesAndWhitespace;
stringByConvertingHTMLToPlainText
也会删除换行符。我尝试在该函数中注释一些代码,但会导致崩溃。有什么建议吗? - rohan-patelDaniel的代码基本上非常好,我修复了一些问题:
删除了NSScanner跳过字符的设置(否则两个连续实体之间的空格将被忽略)
[scanner setCharactersToBeSkipped:nil];
修复了当有孤立的'&'符号时的解析(我不确定这种情况下的“正确”输出是什么,我只是将其与Firefox进行了比较):
例如:
&#ABC DF & B' & C' Items (288)
- (NSString *)stringByDecodingXMLEntities {
NSUInteger myLength = [self length];
NSUInteger ampIndex = [self rangeOfString:@"&" options:NSLiteralSearch].location;
// Short-circuit if there are no ampersands.
if (ampIndex == NSNotFound) {
return self;
}
// Make result string with some extra capacity.
NSMutableString *result = [NSMutableString stringWithCapacity:(myLength * 1.25)];
// First iteration doesn't need to scan to & since we did that already, but for code simplicity's sake we'll do it again with the scanner.
NSScanner *scanner = [NSScanner scannerWithString:self];
[scanner setCharactersToBeSkipped:nil];
NSCharacterSet *boundaryCharacterSet = [NSCharacterSet characterSetWithCharactersInString:@" \t\n\r;"];
do {
// Scan up to the next entity or the end of the string.
NSString *nonEntityString;
if ([scanner scanUpToString:@"&" intoString:&nonEntityString]) {
[result appendString:nonEntityString];
}
if ([scanner isAtEnd]) {
goto finish;
}
// Scan either a HTML or numeric character entity reference.
if ([scanner scanString:@"&" intoString:NULL])
[result appendString:@"&"];
else if ([scanner scanString:@"'" intoString:NULL])
[result appendString:@"'"];
else if ([scanner scanString:@""" intoString:NULL])
[result appendString:@"\""];
else if ([scanner scanString:@"<" intoString:NULL])
[result appendString:@"<"];
else if ([scanner scanString:@">" intoString:NULL])
[result appendString:@">"];
else if ([scanner scanString:@"&#" intoString:NULL]) {
BOOL gotNumber;
unsigned charCode;
NSString *xForHex = @"";
// Is it hex or decimal?
if ([scanner scanString:@"x" intoString:&xForHex]) {
gotNumber = [scanner scanHexInt:&charCode];
}
else {
gotNumber = [scanner scanInt:(int*)&charCode];
}
if (gotNumber) {
[result appendFormat:@"%C", (unichar)charCode];
[scanner scanString:@";" intoString:NULL];
}
else {
NSString *unknownEntity = @"";
[scanner scanUpToCharactersFromSet:boundaryCharacterSet intoString:&unknownEntity];
[result appendFormat:@"&#%@%@", xForHex, unknownEntity];
//[scanner scanUpToString:@";" intoString:&unknownEntity];
//[result appendFormat:@"&#%@%@;", xForHex, unknownEntity];
NSLog(@"Expected numeric character entity but got &#%@%@;", xForHex, unknownEntity);
}
}
else {
NSString *amp;
[scanner scanString:@"&" intoString:&]; //an isolated & symbol
[result appendString:amp];
/*
NSString *unknownEntity = @"";
[scanner scanUpToString:@";" intoString:&unknownEntity];
NSString *semicolon = @"";
[scanner scanString:@";" intoString:&semicolon];
[result appendFormat:@"%@%@", unknownEntity, semicolon];
NSLog(@"Unsupported XML character entity %@%@", unknownEntity, semicolon);
*/
}
}
while (![scanner isAtEnd]);
finish:
return result;
}
iOS 7以后,您可以使用带有NSHTMLTextDocumentType
属性的NSAttributedString
来本地解码HTML字符:
NSString *htmlString = @" & & < > ™ © ♥ ♣ ♠ ♦";
NSData *stringData = [htmlString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *options = @{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType};
NSAttributedString *decodedString;
decodedString = [[NSAttributedString alloc] initWithData:stringData
options:options
documentAttributes:NULL
error:NULL];
解码后的属性字符串将显示为: & & < > ™ © ♥ ♣ ♠ ♦。
注意:仅当在主线程上调用时才起作用。
&#<number>;
形式时,它们被称为数字实体引用。基本上,这是应该被替换的字节的字符串表示形式。在&
的情况下,它代表ISO-8859-1字符编码方案中值为38的字符,即&
。&#
和;
之间的值匹配的字节替换实体。我不知道有什么很好的方法在objective C中实现这一点,但是这个stack overflow问题可能会有所帮助。/// Get a string where internal characters that are escaped for HTML are unescaped
//
/// For example, '&' becomes '&'
/// Handles   and 2 cases as well
///
// Returns:
// Autoreleased NSString
//
- (NSString *)gtm_stringByUnescapingFromHTML;
我只需要在项目中包含三个文件:头文件、实现文件和 GTMDefines.h
。
- (NSString *)stringByDecodingXMLEntities {
NSUInteger myLength = [self length];
NSUInteger ampIndex = [self rangeOfString:@"&" options:NSLiteralSearch].location;
// Short-circuit if there are no ampersands.
if (ampIndex == NSNotFound) {
return self;
}
// Make result string with some extra capacity.
NSMutableString *result = [NSMutableString stringWithCapacity:(myLength * 1.25)];
// First iteration doesn't need to scan to & since we did that already, but for code simplicity's sake we'll do it again with the scanner.
NSScanner *scanner = [NSScanner scannerWithString:self];
do {
// Scan up to the next entity or the end of the string.
NSString *nonEntityString;
if ([scanner scanUpToString:@"&" intoString:&nonEntityString]) {
[result appendString:nonEntityString];
}
if ([scanner isAtEnd]) {
goto finish;
}
// Scan either a HTML or numeric character entity reference.
if ([scanner scanString:@"&" intoString:NULL])
[result appendString:@"&"];
else if ([scanner scanString:@"'" intoString:NULL])
[result appendString:@"'"];
else if ([scanner scanString:@""" intoString:NULL])
[result appendString:@"\""];
else if ([scanner scanString:@"<" intoString:NULL])
[result appendString:@"<"];
else if ([scanner scanString:@">" intoString:NULL])
[result appendString:@">"];
else if ([scanner scanString:@"&#" intoString:NULL]) {
BOOL gotNumber;
unsigned charCode;
NSString *xForHex = @"";
// Is it hex or decimal?
if ([scanner scanString:@"x" intoString:&xForHex]) {
gotNumber = [scanner scanHexInt:&charCode];
}
else {
gotNumber = [scanner scanInt:(int*)&charCode];
}
if (gotNumber) {
[result appendFormat:@"%C", charCode];
}
else {
NSString *unknownEntity = @"";
[scanner scanUpToString:@";" intoString:&unknownEntity];
[result appendFormat:@"&#%@%@;", xForHex, unknownEntity];
NSLog(@"Expected numeric character entity but got &#%@%@;", xForHex, unknownEntity);
}
[scanner scanString:@";" intoString:NULL];
}
else {
NSString *unknownEntity = @"";
[scanner scanUpToString:@";" intoString:&unknownEntity];
NSString *semicolon = @"";
[scanner scanString:@";" intoString:&semicolon];
[result appendFormat:@"%@%@", unknownEntity, semicolon];
NSLog(@"Unsupported XML character entity %@%@", unknownEntity, semicolon);
}
}
while (![scanner isAtEnd]);
finish:
return result;
}
goto
,因为它是可怕的代码风格。你应该将行 goto finish;
替换为 break;
。 - Stunner+ (NSString*) decodeHtmlUnicodeCharactersToString:(NSString*)str
{
NSMutableString* string = [[NSMutableString alloc] initWithString:str]; // #&39; replace with '
NSString* unicodeStr = nil;
NSString* replaceStr = nil;
int counter = -1;
for(int i = 0; i < [string length]; ++i)
{
unichar char1 = [string characterAtIndex:i];
for (int k = i + 1; k < [string length] - 1; ++k)
{
unichar char2 = [string characterAtIndex:k];
if (char1 == '&' && char2 == '#' )
{
++counter;
unicodeStr = [string substringWithRange:NSMakeRange(i + 2 , 2)];
// read integer value i.e, 39
replaceStr = [string substringWithRange:NSMakeRange (i, 5)]; // #&39;
[string replaceCharactersInRange: [string rangeOfString:replaceStr] withString:[NSString stringWithFormat:@"%c",[unicodeStr intValue]]];
break;
}
}
}
[string autorelease];
if (counter > 1)
return [self decodeHtmlUnicodeCharactersToString:string];
else
return string;
}
这是我使用RegexKitLite框架的方式:
-(NSString*) decodeHtmlUnicodeCharacters: (NSString*) html {
NSString* result = [html copy];
NSArray* matches = [result arrayOfCaptureComponentsMatchedByRegex: @"\\&#([\\d]+);"];
if (![matches count])
return result;
for (int i=0; i<[matches count]; i++) {
NSArray* array = [matches objectAtIndex: i];
NSString* charCode = [array objectAtIndex: 1];
int code = [charCode intValue];
NSString* character = [NSString stringWithFormat:@"%C", code];
result = [result stringByReplacingOccurrencesOfString: [array objectAtIndex: 0]
withString: character];
}
return result;
希望这能对某些人有所帮助。
这是Walty Yeung的答案的Swift版本:
extension String {
static private let mappings = [""" : "\"","&" : "&", "<" : "<", ">" : ">"," " : " ","¡" : "¡","¢" : "¢","£" : " £","¤" : "¤","¥" : "¥","¦" : "¦","§" : "§","¨" : "¨","©" : "©","ª" : " ª","«" : "«","¬" : "¬","®" : "®","¯" : "¯","°" : "°","±" : "±","² " : "²","³" : "³","´" : "´","µ" : "µ","¶" : "¶","·" : "·","¸" : "¸","¹" : "¹","º" : "º","»" : "»&","frac14" : "¼","½" : "½","¾" : "¾","¿" : "¿","×" : "×","÷" : "÷","Ð" : "Ð","ð" : "ð","Þ" : "Þ","þ" : "þ","Æ" : "Æ","æ" : "æ","&OElig" : "Œ","&oelig" : "œ","Å" : "Å","Ø" : "Ø","Ç" : "Ç","ç" : "ç","ß" : "ß","Ñ" : "Ñ","ñ":"ñ",]
func stringByDecodingXMLEntities() -> String {
guard let _ = self.rangeOfString("&", options: [.LiteralSearch]) else {
return self
}
var result = ""
let scanner = NSScanner(string: self)
scanner.charactersToBeSkipped = nil
let boundaryCharacterSet = NSCharacterSet(charactersInString: " \t\n\r;")
repeat {
var nonEntityString: NSString? = nil
if scanner.scanUpToString("&", intoString: &nonEntityString) {
if let s = nonEntityString as? String {
result.appendContentsOf(s)
}
}
if scanner.atEnd {
break
}
var didBreak = false
for (k,v) in String.mappings {
if scanner.scanString(k, intoString: nil) {
result.appendContentsOf(v)
didBreak = true
break
}
}
if !didBreak {
if scanner.scanString("&#", intoString: nil) {
var gotNumber = false
var charCodeUInt: UInt32 = 0
var charCodeInt: Int32 = -1
var xForHex: NSString? = nil
if scanner.scanString("x", intoString: &xForHex) {
gotNumber = scanner.scanHexInt(&charCodeUInt)
}
else {
gotNumber = scanner.scanInt(&charCodeInt)
}
if gotNumber {
let newChar = String(format: "%C", (charCodeInt > -1) ? charCodeInt : charCodeUInt)
result.appendContentsOf(newChar)
scanner.scanString(";", intoString: nil)
}
else {
var unknownEntity: NSString? = nil
scanner.scanUpToCharactersFromSet(boundaryCharacterSet, intoString: &unknownEntity)
let h = xForHex ?? ""
let u = unknownEntity ?? ""
result.appendContentsOf("&#\(h)\(u)")
}
}
else {
scanner.scanString("&", intoString: nil)
result.appendContentsOf("&")
}
}
} while (!scanner.atEnd)
return result
}
}
8
。 - kennytm